This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We have identified 45 Ca-like binding sites on the AChR in membranes using Tb as a probe of those sites in anomalous X-ray scattering experiments. We have a 1-dimensional map of the location of these ions, and the Unwin 3-D model of the AChR, which we wish to begin our mapping of the 3-D localization of these ion binding sites using the teragrid facility. We have embedded the AChR in 510 lipids and an excess of water molecules to fill the volume. We would like to use gromacs to equilibrate this system. We envision using larger simulations with more molecules in the future, and therefore, want to explore the capabilities of Teragrid in order to determine the performance and scaling behavior on different machines.